Android 活动启动后加载映像

我是android开发的新手，我想在第一个任务中获得图像URL后加载图像。当我们点击按钮时，我看到了一个加载图像的教程，我想在活动开始后替换图像。 这是我的主要活动

package kori.dev.kori.activity;

import android.app.ProgressDialog;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Rect;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.design.widget.AppBarLayout;
import android.support.design.widget.CollapsingToolbarLayout;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;

import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.util.TypedValue;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.bumptech.glide.Glide;

import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.client.RestTemplate;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import kori.dev.kori.R;
import kori.dev.kori.adapters.CardAdapter;
import kori.dev.kori.model.Card;
import kori.dev.kori.model.Carte;

/**
 * Created by Thefractus Bombatus on 13/12/2016.
 */

public class MainCard extends AppCompatActivity implements LoadImageTask.Listener{

    private RecyclerView recyclerView;
    private CardAdapter adapter;
    private List<Card> cardList;
    public static Carte[] carte;
    private ProgressDialog progressDialog ;
    private ImageView mImageView;






 @Override
    protected void onCreate(Bundle savedInstanceState) {

        loadtask();
        super.onCreate(savedInstanceState);


        setContentView(R.layout.main_card);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        TextView sub_title = (TextView) findViewById(R.id.sub_title);
        String title_sub = getIntent().getStringExtra("name_cat") ;
        sub_title.setText(title_sub);

         mImageView = (ImageView) findViewById(R.id.test_img);
        Button btn_test = (Button) findViewById(R.id.btn_test);

        btn_test.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.d("ooo",carte[0].getPhoto() );
                new LoadImageTask(MainCard.this).execute(carte[0].getPhoto());
            }
        });




    }



    public void onImageLoaded(Bitmap bitmap) {

        mImageView.setImageBitmap(bitmap);
    }


    public void onError() {
        Toast.makeText(this, "Error Loading Image !", Toast.LENGTH_SHORT).show();
    }

    /**
     * Initializing collapsing toolbar
     * Will show and hide the toolbar title on scroll
     */
    private void initCollapsingToolbar() {
        final CollapsingToolbarLayout collapsingToolbar =
                (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar);
        collapsingToolbar.setTitle("dride");

        AppBarLayout appBarLayout = (AppBarLayout) findViewById(R.id.appbar);
        appBarLayout.setExpanded(true);

        // hiding & showing the title when toolbar expanded & collapsed
        appBarLayout.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
            boolean isShow = false;
            int scrollRange = -1;

            @Override
            public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
                if (scrollRange == -1) {
                    scrollRange = appBarLayout.getTotalScrollRange();
                }
                if (scrollRange + verticalOffset == 0) {
                    collapsingToolbar.setTitle(getString(R.string.app_name));
                    isShow = true;
                } else if (isShow) {
                    collapsingToolbar.setTitle(" ");
                    isShow = false;
                }
            }
        });
    }

    private void loadscren(Carte[] cartes){

        initCollapsingToolbar();

        recyclerView = (RecyclerView) findViewById(R.id.recycler_view);

        cardList = new ArrayList<>();
        adapter = new CardAdapter(this, cardList);

        RecyclerView.LayoutManager mLayoutManager = new GridLayoutManager(this, 2);
        recyclerView.setLayoutManager(mLayoutManager);
        recyclerView.addItemDecoration(new GridSpacingItemDecoration(2, dpToPx(10), true));
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setAdapter(adapter);
        try {
            Glide.with(this).load(R.drawable.carte_sport).into((ImageView) findViewById(R.id.backdrop));
        } catch (Exception e) {
            e.printStackTrace();
        }

        loadalbum(cartes);
    }

    private void loadalbum(Carte[] cartes){

         int[] covers = new int[]{

                R.drawable.album1,
                R.drawable.album2,
                R.drawable.album3,
                R.drawable.album4,
                R.drawable.album5,
                R.drawable.album6,
                R.drawable.album7,
                R.drawable.album8,
                R.drawable.album9,
                R.drawable.album10,
                R.drawable.album11};


        int i = 0;
        for(Carte c :cartes){
            Card a = new Card(c.getCarte(), c.getVendeur(), covers[i]);
            cardList.add(a);
            i++;
        }


        adapter.notifyDataSetChanged();
    }

    /**
     * Adding few albums for testing
     */
    private void loadtask() {


        new android.os.Handler().postDelayed(
                new Runnable() {
                    public void run() {
                        // On complete call either onLoginSuccess or onLoginFailed
                        new HttpRequestTaskCarte().execute();;


                    }
                }, 3000);

    }



    /**
     * RecyclerView item decoration - give equal margin around grid item
     */
    public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {

        private int spanCount;
        private int spacing;
        private boolean includeEdge;

        public GridSpacingItemDecoration(int spanCount, int spacing, boolean includeEdge) {
            this.spanCount = spanCount;
            this.spacing = spacing;
            this.includeEdge = includeEdge;
        }

        @Override
        public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
            int position = parent.getChildAdapterPosition(view); // item position
            int column = position % spanCount; // item column

            if (includeEdge) {
                outRect.left = spacing - column * spacing / spanCount; // spacing - column * ((1f / spanCount) * spacing)
                outRect.right = (column + 1) * spacing / spanCount; // (column + 1) * ((1f / spanCount) * spacing)

                if (position < spanCount) { // top edge
                    outRect.top = spacing;
                }
                outRect.bottom = spacing; // item bottom
            } else {
                outRect.left = column * spacing / spanCount; // column * ((1f / spanCount) * spacing)
                outRect.right = spacing - (column + 1) * spacing / spanCount; // spacing - (column + 1) * ((1f /    spanCount) * spacing)
                if (position >= spanCount) {
                    outRect.top = spacing; // item top
                }
            }
        }
    }

    /**
     * Converting dp to pixel
     */
    private int dpToPx(int dp) {
        Resources r = getResources();
        return Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, r.getDisplayMetrics()));
    }

    private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
        ImageView bmImage;

        public DownloadImageTask(ImageView bmImage) {
            this.bmImage = bmImage;
        }

        protected Bitmap doInBackground(String... urls) {
            String urldisplay = urls[0];
            Bitmap mIcon11 = null;
            try {
                InputStream in = new java.net.URL(urldisplay).openStream();
                mIcon11 = BitmapFactory.decodeStream(in);
            } catch (Exception e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            return mIcon11;
        }

        protected void onPostExecute(Bitmap result) {
            bmImage.setImageBitmap(result);
        }
    }

    public  class HttpRequestTaskCarte extends AsyncTask<Void,Void,Carte[]> {

        @Override
        protected Carte[] doInBackground(Void... params) {
            try {
                final String url = "http://ayelive.xyz/website/testRest/RestController.php?carte=shopping";
                RestTemplate restTemplate = new RestTemplate();
                restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
                Carte[] greeting = restTemplate.getForObject(url, Carte[].class);
                return greeting;
            } catch (Exception e) {

                Toast.makeText(MainCard.this, "Error Loading  !", Toast.LENGTH_SHORT).show();
                //Log.e("MainActivity", e.getMessage(), e);
            }

            return null;
        }

        protected void onPreExecute(){

              progressDialog = new ProgressDialog(MainCard.this,
                    R.style.AppTheme_Dark_Dialog);
            progressDialog.setIndeterminate(true);
            progressDialog.setMessage("chargement des elements...");
            progressDialog.show();

        }

        @Override
        protected void onPostExecute(Carte[] greeting) {



            Carte[] greet =greeting;

            carte = greet ;

            Log.d("carte",greet[0].getPhoto());
            Log.d("carte",greet[1].getCarte());

            loadscren(greet);
            progressDialog.dismiss();

        }

    }
}

包kori.dev.kori.activity；
导入android.app.ProgressDialog；
导入android.content.res.Resources；
导入android.graphics.Bitmap；
导入android.graphics.BitmapFactory；
导入android.graphics.Rect；
导入android.os.AsyncTask；
导入android.os.Bundle；
导入android.support.design.widget.AppBarLayout；
导入android.support.design.widget.collappingtoolbarlayout；
导入android.support.v7.app.AppActivity；
导入android.support.v7.widget.DefaultItemAnimator；
导入android.support.v7.widget.GridLayoutManager；
导入android.support.v7.widget.RecyclerView；
导入android.support.v7.widget.Toolbar；
导入android.util.Log；
导入android.util.TypedValue；
导入android.view.view；
导入android.widget.Button；
导入android.widget.ImageView；
导入android.widget.TextView；
导入android.widget.Toast；
导入com.bumptech.glide.glide；
导入org.springframework.http.converter.json.MappingJackson2HttpMessageConverter；
导入org.springframework.web.client.rest模板；
导入java.io.InputStream；
导入java.util.ArrayList；
导入java.util.List；
导入kori.dev.kori.R；
导入kori.dev.kori.adapters.cardapter；
导入kori.dev.kori.model.Card；
导入kori.dev.kori.model.Carte；
/**
*由Fractus Bombatus于2016年12月13日创建。
*/
公共类MainCard扩展AppCompatActivity实现LoadImageTask.Listener{
私人回收站；
专用卡适配器；
私人名单；
公共静态点菜[]点菜；
私有进程对话；
私有图像视图mImageView；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
loadtask（）；
super.onCreate（savedInstanceState）；
setContentView（R.layout.main_卡）；
Toolbar Toolbar=（Toolbar）findViewById（R.id.Toolbar）；
设置支持操作栏（工具栏）；
getSupportActionBar（）.setDisplayHomeAsUpEnabled（true）；
TextView sub_title=（TextView）findViewById（R.id.sub_title）；
字符串title_sub=getIntent（）.getStringExtra（“name_cat”）；
sub_title.setText（title_sub）；
mImageView=（ImageView）findViewById（R.id.test\u img）；
按钮btn_测试=（按钮）findViewById（R.id.btn_测试）；
btn_test.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图）{
Log.d（“ooo”，carte[0].getPhoto（））；
新建LoadImageTask（MainCard.this）.execute（carte[0].getPhoto（））；
}
});
}
已加载公用无效onImageLoaded（位图）{
设置图像位图（位图）；
}
公开无效{
Toast.makeText（这是“加载图像时出错！”，Toast.LENGTH_SHORT.show（）；
}
/**
*初始化折叠工具栏
*将在滚动条上显示和隐藏工具栏标题
*/
私有void initCollasingToolbar（）{
最终折叠工具栏布局折叠工具栏=
（折叠工具栏布局）findViewById（R.id.折叠工具栏）；
折叠工具栏.setTitle（“dride”）；
AppBarLayout AppBarLayout=（AppBarLayout）findViewById（R.id.appbar）；
appBarLayout.setExpanded（true）；
//工具栏展开和折叠时隐藏和显示标题
appBarLayout.addOnOffsetChangedListener（新的appBarLayout.OnOffsetChangedListener（）{
布尔isShow=false；
int scrollRange=-1；
@凌驾
公共无效onOffsetChanged（AppBarLayout AppBarLayout，int verticalOffset）{
如果（滚动范围==-1）{
scrollRange=appBarLayout.getTotalScrollRange（）；
}
如果（滚动范围+垂直偏移==0）{
collasingToolbar.setTitle（getString（R.string.app_name））；
isShow=true；
}否则，如果（isShow）{
折叠Toolbar.setTitle（“”）；
isShow=假；
}
}
});
}
专用无效装载单（Carte[]cartes）{
initcollasingToolbar（）；
recyclerView=（recyclerView）findViewById（R.id.recycler\u视图）；
cardList=newarraylist（）；
适配器=新卡适配器（此，卡列表）；
RecyclerView.LayoutManager mLayoutManager=新的GridLayoutManager（这个，2）；
recyclerView.setLayoutManager（mLayoutManager）；
recyclerView.addItemDecoration（新的GridSpacingItemDecoration（2，dpToPx（10），真））；
setItemAnimator（新的DefaultItemAnimator（））；
recyclerView.setAdapter（适配器）；
试一试{
滑翔。带（这个）。装载（R.drawable.carte_sport）。进入（（图像视图）findViewById（R.id.Background））；
}捕获（例外e）{
e、 printStackTrace（）；
}
装入相册（点菜）；
}
专用void loadalbum（点菜[]点菜）{
int[]封面=新int[]{
R.drawable.album1，
R.drawable.2，
R.drawable.3，
R.drawable.4，
R.drawable.5，
R.drawable.6，
R.drawable.7，
R.drawable.8，
R.drawable.9，
R.drawable.10，
R.drawable.11}；
int i=0；
对于（点菜c：点菜）{
卡a=新卡（c.getCarte（），c.getVendeur（），封面[i]）；
卡片列表。添加（a）；
i++；
}
adapter.notifyDataSetChanged（）；
}
/**
*添加少量相册进行测试
*/
私有void loadtask（）{
新的android.os.Handler（）.postDelayed(
新的Runnable（）{
公开募捐{
/
package kori.dev.kori.activity;

/**
 * Created by THEOPHRACTUS on 23/12/2016.
 */

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.Log;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

public class LoadImageTask extends AsyncTask<String, Void, Bitmap> {

    public LoadImageTask(Listener listener) {

        mListener = listener;
    }

    public interface Listener{

        void onImageLoaded(Bitmap bitmap);
        void onError();
    }

    private Listener mListener;
    @Override
    protected Bitmap doInBackground(String... args) {

        try {
//Log.d("cat",args[0]);
            return BitmapFactory.decodeStream((InputStream)new URL(args[0]).getContent());

        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Bitmap bitmap) {

        if (bitmap != null) {

            mListener.onImageLoaded(bitmap);

        } else {

            mListener.onError();
        }
    }
}

package kori.dev.kori.adapters;

import android.content.Context;
import android.content.Intent;
import android.support.v7.widget.PopupMenu;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.bumptech.glide.Glide;

import java.util.List;

import kori.dev.kori.R;
import kori.dev.kori.activity.DetailActivity;
import kori.dev.kori.model.Card;

/**
 * Created by Thefractus Bombatus on 13/12/2016.
 */

public class CardAdapter extends RecyclerView.Adapter<CardAdapter.MyViewHolder> {

    private Context mContext;
    private List<Card> cardList;

    public class MyViewHolder extends RecyclerView.ViewHolder {
        public TextView title, count;
        public ImageView thumbnail, overflow;

        public MyViewHolder(View view) {
            super(view);
            title = (TextView) view.findViewById(R.id.title);
            count = (TextView) view.findViewById(R.id.count);
            thumbnail = (ImageView) view.findViewById(R.id.thumbnail);
            overflow = (ImageView) view.findViewById(R.id.overflow);
        }
    }


    public CardAdapter(Context mContext, List<Card> cardList) {
        this.mContext = mContext;
        this.cardList = cardList;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.categorie_card, parent, false);

        return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, int position) {
        Card card = cardList.get(position);
        holder.title.setText(card.getCatName());
        holder.count.setText(card.getEntrName() );

        // loading album cover using Glide library
        Glide.with(mContext).load(card.getThumbnail()).into(holder.thumbnail);

        holder.overflow.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                showPopupMenu(holder.overflow);
            }
        });
    }

    /**
     * Showing popup menu when tapping on 3 dots
     */
    private void showPopupMenu(View view) {
        // inflate menu
        PopupMenu popup = new PopupMenu(mContext, view);
        MenuInflater inflater = popup.getMenuInflater();
        inflater.inflate(R.menu.menu_categorie, popup.getMenu());
        popup.setOnMenuItemClickListener(new MyMenuItemClickListener());
        popup.show();
    }

    /**
     * Click listener for popup menu items
     */
    class MyMenuItemClickListener implements PopupMenu.OnMenuItemClickListener {

        public MyMenuItemClickListener() {
        }

        @Override
        public boolean onMenuItemClick(MenuItem menuItem) {
            switch (menuItem.getItemId()) {
                case R.id.action_add_favourite:
                    Toast.makeText(mContext, "Ajouter au panier", Toast.LENGTH_SHORT).show();
                    return true;
                case R.id.action_play_next:
                    Intent intent = new Intent(mContext, DetailActivity.class);
                    mContext.startActivity(intent);

                    return true;
                default:
            }
            return false;
        }
    }

    @Override
    public int getItemCount() {
        return cardList.size();
    }
}

compile 'com.squareup.picasso:picasso:2.5.2'

 btn_test.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Log.d("ooo",carte[0].getPhoto());
            Picasso
               .with(view.getContext())
               .load(carte[0].getPhoto())
               .into(mImageView);
         }
  });